TELNET OUTPUT HORIZONTAL TABSTOPS OPTION
RFC 653, NIC 31156 (Oct. 25, 1974)
D. Crocker (UCLA-NMC)
Online file: [ISI]NAOHTS.TXT
TELNET OUTPUT HORIZONTAL TABSTOPS OPTION
1. Command name and code
NAOHTS 11 (Negotiate About Output Horizontal Tabstops)
2. Command meanings
In the following, we are discussing a simplex connection, as described in
the NAOL and NAOP Telnet options.
IAC DO NAOHTS
The data sender requests or agrees to negotiate about output
horizontal tabstops with the data receiver. In the case where
agreement has been reached and in the absence of further
subnegotiations, the data receiver is assumed to be handling output
horizontal tabstops.
IAC DON'T NAOHTS
The data sender refuses to negotiate about output horizontal tabstops
with the data receiver, or demands a return to the unnegotiated
default mode.
IAC WILL NAOHTS
The data receiver requests or agrees to negotiate about output
horizontal tabstops with the sender. In the case where agreement has
been reached and in the absence of further subnegotiations, the data
receiver alone is assumed to be handling output horizontal tabstops.
IAC WON'T NAOHTS
The data receiver refuses to negotiate about output horizontal
tabstops, or demands a return to the unnegotiated default mode.
IAC SB NAOHTS DS <8-bit value> ... <8-bit value> IAC SE
The data sender specifies, with the 8-bit value(s), which party should
handle output horizontal tabstop considerations and what the stops
should be. The code for DS is 1.
IAC SB NAOHTS DR <8-bit value> ... <8-bit value> IAC SE
The data receiver specifies, with the 8-bit value(s), which party
should handle output horizontal tabstop considerations and what the
stops should be. The code for DR is 0.
3. Default
DON'T NAOHTS/WON'T NAOHTS.
In the default absence of negotiations concerning which party, data
sender or data receiver, is handling output horizontal tabstops, neither
party is required to handle them and neither party is prohibited from
handling them; but it is appropriate if at least the data receiver
handles horizontal tabstops, albeit primitively.
4. Motivation for the Option
Please refer to section 4 of the NAOL and of the NAOP Telnet option
descriptions.
5. Description of the Option
The data sender and the data receiver use the 8-bit value(s) along with the
DS and DR SB subcommands as follows (multiple 8-bit values are allowed only
if each is greater than zero and less than 251):
8-bit value : Meaning :
0 Command sender suggests that he alone will handle
tabstops, for the connection.
1 to 250 Command sender suggests that the other party alone
should handle tabstop considerations, but suggests
that the indicated value(s) be used. The value(s)
are the column numbers, relative to the physical
left side of the printer page or terminal screen,
that are to be set.
251 to 254 Not allowed, in order to be compatible with
related Telnet options.
255 Command sender suggests that the other party alone
should handle output tabstops and suggests nothing
about how it should be done.
The guiding rules are that:
(1) if neither data receiver nor data sender wants to handle output
horizontal tabstops, the data receiver must do it, and
(2) if both data receiver and data sender want to handle output
horizontal tabstops, the data sender gets to do it.
The reasoning for the former rule is that if neither wants to do it, then
the default in the NAOHTS option dominates. If both want to do it, the
sender, who is presumed to have special knowledge about the data, should be
allowed to do it, taking into account any suggestions the receiver may make.
As with all option negotiations, neither party should suggest a state
already in effect except to refuse to negotiate; changes should be
acknowledged; and once refused, an option should not be resuggested until
"something changes" (e.g., another process starts).
At any time, either party can disable further negotiation by giving the
appropriate WON'T NAOHTS or DON'T NAOHTS command.